My view is that humans NATURALLY live to be about 80s or their 100s but that extraordinary medicine can be used to keep them fit or firm into their 200s if they choose (where they'll be completely decrypt). I wouldn't be surprised if there's "regeneration therapies" and organ replacements at a fairly regular rate.

I also tend to view a certain quality of life element that a Starfleet Captain with access to Federation tech nonstop is going to be better off than your average citizen on a colony world. So most people would live until they're 140s or 150 then just let themselves die than trying to squeeze EVERY moment out of their lives.